Cellular respiration is vital for living organisms as it converts nutrients into ATP, the energy currency of cells. This process allows cells to perform essential functions such as growth, reproduction, and response to stimuli. It occurs in two main stages: glycolysis and the Krebs cycle, followed by oxidative phosphorylation. By breaking down carbohydrates, fats, and proteins, cellular respiration releases energy stored in chemical bonds, thus sustaining life. Moreover, this process also involves the consumption of oxygen and the production of carbon dioxide, playing a critical role in maintaining ecosystem balance.